Optical reader having inclinable stage which mounts optical unit thereon

ABSTRACT

An optical reader which is compatible with every environment irrespective of installation and usage environments, thereby enabling uniform manufacturing, satisfactory reading reliance, and operative safety and user-friendliness. The optical unit is mounted on the stage, and there is provided an inclination apparatus which inclines the stage at a desired angle. Thereby, without changing a preset optimal scanning pattern, only its emitting direction becomes changeable freely.

This application is a division of prior application Ser. No. 09/253,943filed Feb. 22, 1999.

BACKGROUND OF THE INVENTION

The present invention relates generally to optical readers, and moreparticularly to an optical reader that changes a light scanningdirection. The optical reader of the present invention is especiallysuitable for barcode scanners which optically read barcode put onmerchandises in POS systems and the like.

Recently, barcode scanners have become more frequently used for cashiersin supermarkets, discount stores, home centers, etc. In general,operators who use a barcode scanner fixed onto a cashier table move amerchandise on which a barcode is printed, whereby the merchandise maygo across a scanning pattern emitted in a predetermined direction from aread window of the barcode scanner.

The scanning pattern is usually fixed to one pattern, and its emittingdirection is preset and fixed in accordance with the installation andusage environments of the scanner at the time of manufacturing. The“installation environment”, as used herein, means a direction in whichthe read window is to be installed in a cashier table; more concretely,whether the read window is arranged parallel or perpendicular to thecashier table. The former barcode scanner is called a lateral type, andthe latter a longitudinal type. The “usage environment”, as used herein,means a moving path of a merchandise onto which a barcode is printed;for example, whether the merchandise is to be moved from right to leftor left to right, even in the same lateral type. The usage environmentdepends upon each operator's height, experience and the like. Theemitting direction is usually preset and inclined by a predeterminedangle relative to a direction perpendicular to the read window, towardan upper stage from which a merchandise comes (for instance, which is aright side if the merchandise moves from right to left).

With the spread of barcode scanners, prompt reading of barcodes andefficient manufacturing of the barcode scanners has been stronglydemanded.

However, the conventional longitudinal and lateral barcode scanners aredifferent in manipulation and optimal scanning-pattern emittingdirection. Even in the same lateral type, a proper emitting direction isdifferent between one which moves merchandises from right to left, andanother which moves merchandises from left to right. Therefore, in anattempt to install and use the conventional barcode scanners each storehas ordered apparatuses having a different pattern emitting directionswhich correspond to their installation and usage environments.

A change of the emitting direction requires a change of inclination ofan optical system that generates a scanning pattern and/or anarrangement of optical element(s). Consequently, each barcode scannereven for the same type should be manufactured differently in emittingdirection every business type of different installation and usageenvironments, causing inefficient manufacturing and price increasing. Onthe other hand, primary for manufacturing purposes, there have beenproposed apparatuses having a fixed emitting direction while theinstallation and usage environments are ignored, but these apparatusescannot generate an optimal pattern to achieve an object of promptreading.

On the other hand, the actual prompt reading depends, in addition to thescanning pattern, upon a moving path of merchandise (or barcode) by anoperator. Even in a barcode scanner in which the scanning pattern isfixed to the optimal pattern for the installation and usageenvironments, a moving path slightly different among operators dependingupon their heights, experiences, skillful hands, habits, etc.Disadvantageously, each operator should adjust a barcode moving path andspend a long time to master the operating skill.

To eliminate these problems, applicant has proposed, in JapaneseLaid-Open Patent Application No. 9-16705, a barcode reader thatgenerates a plurality of scanning patterns by making mirrors movable inthe optical system, extending a scan area, and selects one frequentlyused scanning pattern from them. Nevertheless, this invention wasdisadvantageous since it has a low reading reliance and does not alwaysmeet operative safety requirements.

The scanning pattern frequently used in this reference is not the actualoptimal scanning pattern that has a high barcode-reading reliance. Theoptimal scanning pattern is one determined as a result of simulationtaking into account the arrangement between a laser source and a lightreceiving element, while minimizing optical noises caused by mirrorangles and the light amount of the laser beam. A scanning patternincluding optical noises, even though hitting a barcode, cannot properlyread the barcode data. For instance, a certain mirror angle puts thereflected light over store's light as a noise, and the light receivingelement receives a large amount of incident light. A laser beamreflected at an edge or the like of the reflection mirror also causes alarge amount of light incident to the light receiving element. In thisway, a plurality of scanning patterns which have been generated only bytaking into account the usage environment without paying attention tothe optical noises would lower the reading reliance and delay thereading time. It is preferable to maintain the optimal scanning patternthat is set at the time of manufacturing.

In addition, as seen in the International Standard IEC and the U.S.Standard CDRH which take care of human eyes subject to a laser beam, thelaser safety standards define certain restrictions to the light amountof an incident laser beam. However, the light amount of an arbitrarilychanged scanning pattern would not necessarily meet the above standards,endangering safety.

BRIEF SUMMARY OF THE INVENTION

Accordingly, it is a general object of the present invention to providea novel and useful optical reader in which the above disadvantages areeliminated.

More specifically, it is another object to provide an optical readerwhich enables uniform manufacturing irrespective of the installation andusage environments.

It is still another object of the present invention to provide anoptical reader that is user-friendlier than the conventional ones.

It is another object of the present invention to provide an opticalreader which maintains the optimal scanning pattern and has a highreading reliance.

It is still another object of the present invention to provide anoptical reader that meets the laser safety standards and secures safety.

In order to achieve the above objects, an optical device of the presentinvention comprises an optical unit which generates a predeterminedscanning pattern, emits the predetermined scanning pattern to anoptically readable medium, and receives light reflected from the medium,a stage which mounts an optical system at least necessary to generatethe predetermined scanning pattern from among the optical unit, and aninclination apparatus which inclines the stage.

Another optical device of the present invention comprises an opticaldevice which includes a housing having a plurality of reading windows, aplurality of optical units accommodated in said housing, the number ofthe optical units corresponding to the number of reading windows, eachoptical unit generating a predetermined scanning pattern, emitting thepredetermined scanning pattern to an optically readable medium, andreceiving light reflected from the medium, a stage, accommodated in thehousing, which mounts an optical system at least necessary to generatethe predetermined scanning pattern from among the optical unit, and aninclination apparatus. accommodated in the housing, which inclines thestage.

Still another optical device of the present invention comprises anoptical unit which generates a predetermined scanning pattern, emits thepredetermined scanning pattern to an optically readable medium, andreceives light reflected from the medium, a stage which mounts anoptical system at least necessary to generate the predetermined scanningpattern from among the optical unit, an inclination apparatus whichinclines the stage, and a controller connected to the inclinationapparatus, the controller controlling inclination of the stage by theinclination apparatus.

A scanning method of the present invention comprises the steps ofgenerating a predetermined scanning pattern to read out an opticallyreadable medium, changing an emitting direction of the predeterminedscanning pattern to a desired direction while maintaining thepredetermined pattern, emitting the predetermined scanning pattern tothe desired direction, and reading out light reflected from the mediumbased on the predetermined pattern.

An optical device of the present invention comprises an optical unitwhich generates a predetermined scanning pattern, emits thepredetermined scanning pattern to an optically readable medium, andreceives light reflected from the medium, and an inclinable stage whichmounts an optical system at least necessary to generate thepredetermined scanning pattern from among the optical unit.

Thus, the optical readers and scanning method of the present inventionmay change a scanning-pattern emitting direction while maintaining thepredetermined scanning pattern.

Other objects and further features of the present invention will becomereadily apparent from the following description and accompanyingdrawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing a principle of a barcode scanner of afirst embodiment according to the present invention.

FIG. 2 shows an arrangement of essential part of a typical optical unitfor use with the barcode scanner according to the present invention.

FIG. 3 is a perspective view of essential part of a modified example ofa reflection mirror of the optical unit shown in FIG. 2.

FIG. 4 is a side view of essential part of arrangement between a polygonmirror and a fixed mirror group in the optical unit shown in FIG. 2.

FIG. 5 is a perspective view of essential part of arrangement between apolygon mirror and a fixed mirror group in the optical unit shown inFIG. 2.

FIG. 6 is a transparent perspective view of essential part of oneexample of inclination apparatus of the barcode scanner shown in FIG. 1.

FIG. 7 is a partially sectional and perspective view showing essentialpart of exemplary connections that realize the inclination apparatusshown in FIG. 6.

FIG. 8 is a perspective view for explaining an effect of the barcodescanner shown in FIG. 6.

FIG. 9 is a perspective view for explaining another effect of thebarcode scanner shown in FIG. 6.

FIG. 10 is a schematic perspective view of a modified example of theinclination apparatus shown in FIG. 6.

FIG. 11 is a transparent perspective view of essential part of anothermodified example of the inclination apparatus shown in FIG. 6.

FIG. 12 is a block diagram showing a principle of a barcode scanner of asecond embodiment according to the present invention.

FIG. 13 is a transparent perspective view of essential part showingstill another modified example of the inclination apparatus shown inFIG. 6.

FIG. 14 is a perspective view of essential part showing another exampleof the inclination apparatus of the barcode scanner shown in FIG. 1.

FIG. 15 is a side view of the inclination apparatus shown in FIG. 14.

FIG. 16 is a schematic perspective view of a modified example of theinclination apparatus shown in FIG. 14.

FIG. 17 is a block diagram showing a principle of a barcode scanner of athird embodiment according to the present invention.

FIG. 18 is a block diagram showing a principle of a barcode scanner of afourth embodiment according to the present invention.

FIG. 19 is a perspective view of product detecting sensors applicable tothe barcode scanners shown in FIGS. 17 and 18.

FIG. 20 is a flowchart of control procedures of a CPU shown in FIGS. 17and 18.

FIG. 21 shows a scanning pattern emitted from a read window.

FIG. 22 is a diagram for explaining automatic control of the inclinationapparatus shown in FIG. 6.

FIG. 23 is a diagram for explaining automatic control of the inclinationapparatus shown in FIG. 10.

FIG. 24 is a diagram for explaining automatic control of the inclinationapparatus shown in FIG. 14.

FIG. 25 is a diagram for explaining automatic control of an inclinationapparatus different from the inclination apparatus in FIG. 23.

FIG. 26 is a plane view for explaining an example of mechanicalrestriction to an inclined angle of the inclination apparatus shown inFIG. 6.

FIG. 27 is a view for explaining a concrete effect of the barcodescanner according to the present invention.

FIG. 28 is another view for explaining a concrete effect of the barcodescanner according to the present invention.

FIG. 29 is still another view for explaining a concrete effect of thebarcode scanner according to the present invention.

FIG. 30 is a schematic perspective view of a barcode scanner (two-facedscanner) of a fifth embodiment according to the present invention.

FIG. 31 is a schematic perspective view of the barcode scanner shown inFIG. 30 in which a bending angle is a right angle.

FIG. 32 is a side view showing a relationship between a bending angleand an emitting direction of a scanning pattern in the barcode scannerin FIG. 30.

FIG. 33 is a side view for explaining a sweet spot of the barcodescanner shown in FIG. 31.

FIG. 34 is a side view for explaining a sweet spot of the barcodescanner shown in FIG. 30.

FIG. 35 is a transparent perspective view of essential part showing aninner structure of the barcode scanner shown in FIG. 30.

FIG. 36 is a top view for explaining a reading direction indicator ofthe barcode scanner shown in FIG. 30.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to the accompanying drawings, a description will be given ofbarcode scanner 10A of a first embodiment according to the presentinvention. Hereinafter, the same elements are designated by the samereference numerals, and a description thereof will be omitted. Inaddition, in the following description, barcode scanner 10 generalizesbarcode scanners 10A, 10B, etc.

The barcode scanner 10A of the present invention, formed as arectangular parallel shaped module (housing 12), emits a scanningpattern onto a barcode as a readable object through read window 14 inthe housing 12, receives light reflected from the barcode, and reads thebarcode data. The housing 12 may includes a plurality of read windows oris formed to be bendable, as seen in barcode scanner 10E which will bedescribed later with reference to FIG. 30.

The barcode scanner 10A in FIG. 1 includes optical unit 100 whichgenerates a scanning pattern, emits it in a predetermined direction, andreceives light reflected from a barcode, stage 200 which mounts theoptical unit 100, inclination apparatus 300 which inclines the stage 200with the optical unit 100, and CPU 400 which controls the optical unit100. Optionally, the CPU 400 may control the inclination apparatus 300,but this embodiment will be described later as barcode scanner 10C withreference to FIG. 18. The barcode scanner 10A may further includeinterface part 410 for exchanging data with an external POS terminal, adisplay part 420 which informs an operator whether it has recognizedvalidly barcode data, and speaker 422, or the like.

As shown in FIG. 2, the optical unit 100 includes light source 110,light collecting mirror 120 having, at a center thereof, reflectionmirror 130 as a plane mirror part, polygon mirror 140, and fixed mirrorgroup 150, and light receiving part 160. This arrangement is merely onetypical example of an optical unit. In addition, a size of each elementis relatively exaggerated for description purposes. The optical unit 100for use with the barcode scanner 10 of the present invention may broadlyinclude, in addition to this structure, those optical units which emit abeam and scan a barcode; for instance, an optical unit which emits abeam from a polygon mirror directly onto a barcode without interveningfixed mirror group, and an optical unit which emits a beam from a lightsource to a polygon mirror without intervening a reflection mirror. Ingeneral, if there are provided a plurality of optical units 100, aplurality of stages 200 and inclination apparatuses 300 are providedaccordingly.

The light source 110 generates a laser beam or infrared ray (simplyrefereed to as “beam” hereinafter) and emits it toward (the reflectionmirror 130 provided at the center of) the light collecting mirror 120.The light source 110 may utilize a semiconductor laser, a He—Ne lasertube, etc. The light source 110 is driven light control circuit 112shown in FIG. 1 that controls turning on/off of the beam. The lightcontrol circuit 112 is connected to and controlled by the CPU 400. Asolid line arrow in FIG. 2 indicates a beam emitted from the lightsource 110.

The light collecting mirror 120 has a concave mirror shape having circlewindow 122 at a center thereof. The reflection mirror 130 is set as aplane mirror at the circle window 122. The light collecting mirror 120is made of one resin molded product including concave mirror 124 and thereflection mirror 130. Of course, the reflection mirror 130 may be madeas a different member independent of the light collecting mirror 120.

In this embodiment, the concave mirror 124 in the light collectingmirror 120 receives light which includes barcode data and has beenreflected from the polygon mirror 140, stops down it to a predeterminedspot diameter, and reflects it to the light receiving part 160. A brokenline arrow from the light collecting mirror 120 to the light receivingpart 160 in FIG. 2 indicates the reflected light. Optionally, the lightcollecting mirror 120 may be substituted by a collimeter lens having thesimilar functions (or a combination of the collimeter lens and acylindrical lens etc.).

The reflection mirror 130 in the light collecting mirror 10 reflects abeam emitted from the light source 110 to the polygon mirror 140.Optionally, the reflection mirror 130 may serve to reflect lightreflected from the polygon mirror to the light receiving part 160.

Optionally, as shown in FIG. 3, the reflection mirror 130 may becomprised of swing mirror 134 which is swingable around shaft 132orthogonal to a rotational axis 143 of the polygon mirror 140 which willbe described later. Swing of the reflection mirror 130 (134) generates aplurality of scanning patterns which are mutually shifted, improving thereading precision. The shift width of the scanning pattern is set to avalue at least higher than the value (7 mm) defined in the laser safetystandards, and it is designed that the shifted scanning patterns nevergo into operator's pupil(s).

As shown in FIGS. 1 through 5, the polygon mirror 140 has a plurality ofreflection surfaces 142 and rotational axis 143, and is connected motor144 that rotates the polygon mirror 140. The motor 144 is connected toangle detecting device 146 which detects a rotational angle of a motorshaft (not shown) of the motor 144, and motor driving circuit 148 whichdrives the motor 144. Optionally, magnet 147 and hole element 149 areprovided to detect a home position (i.e., reference position) of thepolygon mirror 140. Either the magnet 147 or the hole element 149rotates with the polygon mirror 140, whereas the other stands still withthe stage 200.

The polygon mirror 140 reflects beam light reflected from the reflectionmirror 130 to the fixed mirror group 150, and reflects light includingthe barcode data reflected from the fixed mirror group 150 to thereflection mirror 130. The desired number of reflection surfaces 142 maybe provided, and each reflection surface 142 has a different inclinationin the instant embodiment. For example, the polygon mirror 140 is formedas a square pillar for four reflection surfaces 142, and a pentagonalpillar for five reflection surfaces 142. The motor shaft (not shown) ofthe motor 144 is the same shaft as the rotational axis 143 of thepolygon mirror 140, and the polygon mirror 140 (or the respectivereflection surfaces 142) rotates around the rotational axis 143.

The angle detecting device 146 and the motor driving circuit 148 areconnected to and controlled by the CPU 400. Any angle detecting means(for instance, a potentiometer) that has been known in the art isapplicable to the angle detecting device 146.

The fixed mirror group 150 includes a plurality of (e.g., five)stationary mirrors (or also called “scan mirrors”) 152. The fixed mirrorgroup 150 emits, as a scanning pattern, a beam light reflected from thepolygon mirror 140 through the read window 14 to a barcode so as to scanit, and reflects light reflected by the barcode to the polygon mirror140. Since each reflection surface 142 of the polygon mirror 140 isinclined differently, one stationary mirror 152 emits a beam in aplurality of directions (for example, three directions for threeinclined angles). When five stationary mirrors are used, as shown inFIGS. 2, 4 and 5, the stationary mirrors 152 includes a pair ofoutermost V mirrors 154, a pair of H mirrors 156 adjacent to the Vmirrors 154, and one center Z mirror 158. Beams reflected by thesestationary mirrors 152 form a scanning pattern including V pattern 155,H pattern, and Z pattern 159 above the read window 14. Radiation of thisscanning pattern onto a barcode above the read window 14 results in thereflected light including the barcode data.

The light receiving part 160 includes light receiving element 162 suchas a pin photodiode etc., and A/D converter part 164. The lightreceiving element 162 receives light reflected from a barcode throughthe reflection mirror 130 which proceeds reverse to the beam andincludes the barcode data, converts it into an analog signal, and thensends it to the A/D converter part 164. The A/D converter part 164,connected to the CPU 400, converts the analog signal to a digitalsignal, and sends it to the CPU 400.

A simulation has been previously conducted for the optical unit 400before the unit is shipped so that optical noises become minimum and thelight amount of the scanning pattern meet the laser safety standards(such as IEC and CDRH). Therefore, the optical unit 10 may generate ascanning pattern which always has an optimal reading precision andsecures safety irrespective of the installation and usage environments.

The optical unit 100 is fixed onto the stage 200 which has a plate shapeor any other arbitrary shape. The stage 200 is made of materials, whichhas strength sufficient to support the optical unit 100 (such as an ironplate). The stage 200 does not have to mount all the elements of theoptical unit 100, and may mount only a minimum optical system necessaryto emit a scan beam (e.g., the light source 110, light collecting mirror120, reflection mirror 130, polygon mirror 140, and fixed mirror group150). Optionally, the stage 200 mounts such an optical system asreceives reflected light of a scan beam (such as the light receivingelement 162). In any event, the stage 200 need not mount the lightcontrol circuit 112, angle detecting device 146, and motor drivingcircuit 148, and A/D converter part 164. Here, the “a minimum opticalsystem necessary to emit a scan beam” means an optical system which maymaintain an optimal scanning pattern preset when the product is shipped.Therefore, it does not include inclination that breaks the presetoptimal scanning pattern, for example, by independently inclining onlythe stationary mirror 130. However, for example, in case of using aone-dimensional inclination mechanism which maintains an optical axis ofa beam from the light source 110, the light source 110 may be excludedfrom the stage 200 theoretically. As far as the light reflected from abarcode can be read, the light receiving element 162 may be removed fromthe stage 200. If an element of the optical unit changes, for example,if a collimeter lens is used rather than the light collecting mirror120, “a minimum optical system necessary to emit a scan beam” must alsochange accordingly. Incidentally, the stage 200 may be processed so thatit has part or all of the functions of the inclination apparatus 300which will be described below.

The inclination apparatus 300 is mechanically connected to the stage200, and compatible with various types of inclinations, such as aone-dimensional inclination, two-dimensional inclination, manualinclination, and automatic inclination. The automatic inclination by theCPU 400 will be described later with reference to FIG. 17. Theinclination apparatus 300 includes inclination mechanism 302 whichinclines the stage 200, and securing mechanism 304 which secures thestage 200 at a predetermined inclined angle. Optionally, the inclinationapparatus 300 further includes returning device 306 which returns thestage 200 to the horizontal state, and display 308 which notifies anoperator of a direction and amount of the inclination. In the followingdescription, the inclination apparatus 300 generalizes referencenumerals 300 a, 300 b, etc. that are assigned to inclination apparatusesin the different embodiments. This generalization applies to theinclination mechanism and other elements.

The inclination mechanism 302 may be a one-dimensional inclinationmechanism that one-dimensionally inclines the stage 200 or atwo-dimensional inclination mechanism that two-dimensionally inclinesit. In the following description, the inclination mechanism 302 inclinesthe stage 200 by a mechanical action, but this does not excludeelectric, magnetic and other actions. As described above, theinclination mechanism 302 may be inclined manually by an operator orautomatically by the CPU 400, and the automatic inclination will bediscussed with reference to FIG. 17.

The one-dimensional inclination mechanism is one that inclines the stage200 around a rotational axis that extends in a predetermined direction.An operator can inclines the stage 200 directly or indirectly around therotational axis by applying a moment to the rotational axis, the stage200 or a member coupled with the stage 200. Therefore, theone-dimensional inclination mechanism generally includes such arotational axis and moment application means. The one-dimensionalinclination mechanism has various modifications by types of therotational axis and the moment application means.

A description will now be given of a one-dimensional inclinationmechanism in which a rotational axis is made by support shaft 310coupled to the stage 200 and an operator applies a moment directly ontothe support shaft 310 via direction indicator dial 312 coupled to thesupport shaft 310.

FIG. 6 shows exemplary inclination apparatus 300 a havingone-dimensional inclination mechanism 302 a. As illustrated, the supportshaft 310 as a rotational axis is connected to lower surface 202 of thestage 200 while separated from the lower surface 202 by a predetermineddistance, and supported rotatable with the stage 200 with respect to thehousing 12. A position and sectional shape of the support shaft 310 isnot limited to those shown in FIG. 6. Therefore, the support shaft 310may be connected to the stage 200 while penetrating almost the center ofthe stage 200 or may be connected to the bottom or side of the stage200. In other words, the rotational axis may be positioned in the stage200 or spaced from the stage 200.

FIG. 7 is an exemplary connection between the support shaft 310 and thestage 200 that realizes the inclination mechanism shown in FIG. 6. Asillustrated, the support shaft 310 is attached rotatably to the housing12 via a pair of bearings 311 a and 311 b, and a pair of levers 319 aand 319 b are secured onto the support shaft 310 between the bearings311 a and 311 b. These levers 319 a and 319 b are secured onto the lowersurface 202 of the stage 200. Therefore, the support shaft 310 is ableto rotate together with the stage 200 via the levers 319 a and 319 bwith respect to the housing 12. For purpose of illustrations, gear 314in FIG. 6 which will be described later and other elements are omittedin FIG. 7. Similarly, the bearings 311 a and 311 b and the like areomitted in FIG. 6.

Any bearing known in the art (for example, ball bearing) is applicableto the bearings 311 a and 311 b.

Although FIG. 7 shows that each of the levers 319 a and 319 b has asemi-cylindrical shape having a predetermined width along the supportshaft 310, the shape thereof is not limited to it. Any desired shape maybe selected in accordance with the interval to be spaced between thesupport shaft 310 and the stage 200, and other conditions. Thepredetermined width is set by taking into account the strength necessaryfor achieving stable inclining actions between the support shaft 310 andthe stage 200. Therefore, levers 319 a and 319 b may be made of membershaving different shapes and sizes. The number and positions of leversare not limited to those shown in FIG. 7. The lever may be part of thestage 200, instead of forming an independent member.

As shown in FIGS. 6 and 7, the support shaft 310 penetrates the housing12 at both ends thereof, and one end protrudes as protrusion 310 a fromthe housing 12 and engaged with the direction indicator dial 312. Thedirection indicator dial 312 has any shape as far as it can surelyfunction to indicate an inclined angle as stated below. In FIGS. 6 and7, the direction indicator dial 312 has a sectional shape of acombination of a circle and a triangle.

In the initial state, the stage is set to be “no inclination”(horizontal), and the direction indicator dial 312 indicates 0° in scale313 provided on the housing 12. The scale 313 is omitted in FIGS. 6 and7. Exemplary scale 313 is shown in FIG. 8. The scale 313 may be cutevery five degrees, for example, and produced by a desired method.Alternatively, if more precise angle is required to be indicated, adisplay that electrically responds to a rotation of the directionindicator dial 312 may be provided in addition to or instead of thescale 313.

An operator may incline the stage 200 by an arbitrary angle by rotatingthe direction indicator dial 312. When the stage 200 is inclined, thedirection indicator dial 312 indicates the inclined angle on the scale313.

The inclination apparatus 300 a shown in FIG. 6 includes securingmechanism 304 a that holds the stage 200 at the initial state and theinclined state after inclination. The securing mechanism 304 a maysecure the stage 200 by any known method. For example, referring to FIG.6, the securing mechanism 304 a may be comprised of gear 314 which isconnected coaxially to and rotatable with the support shaft 310, andlock pin 316 which is connected to the housing 12 and movable betweenlock position A and retreat position B in hole 317 in the housing 12.When the lock pin 316 is located at the retreat position B, an operatorcan rotate the direction indicator dial 312. When the lock pin 316 ismoved to the lock position A and engaged with the gear 314, it cansecure the gear 314, thereby securing the support shaft 310 and thestage 200 at that inclination. In an attempt to secure a stableoperation by setting as a normal state the lock state of the stage 200,the lock pin 316 may be forced to the lock position A by a spring memberetc. In this case, the operator moves the lock pin 316 to the retreatposition B before inclining the stage 200.

If the stage 200 need to be returned to the initial state (horizontalstate) after the lock pin 316 is released from fixation, a spring member(not shown) may be provided as return device 306 a. One end of thespring member is fixed onto the bottom of the housing 12 and the otherend is connected to the lower surface 202 of the stage 200.

The scale 313 provided at the side of the housing 12 and the directionindicator dial 312 serve as the display 308 of the inclination apparatus300 a. An operator may always obtain optimal operations by memorizingthe inclined angle and using it for the next setting.

The barcode scanner 10A shown in FIG. 6 may be used as a longitudinaltype, as shown in FIG. 8, or as a lateral type as shown in FIG. 9, forexample. An operator can obtain an inclined angle of the stage 200optimal to him/her by simply adjusting the direction indicator dial 312,irrespective of his/her height and experience. Therefore, the barcodescanner 10A shown in FIGS. 6 and 7 may change a pattern emittingdirection in accordance with the installation and usage environmentswhile maintaining the optimal pattern preinstalled at the time ofshipping.

Referring to FIG. 6, although the rotational axis is made of the supportshaft 310 which is an independent member, it is not necessary toconstitute the rotational axis by an independent member, it is notnecessary to constitute the rotational example, FIG. 10 schematicallyshows inclination apparatus 300 b having one-dimensional inclinationmechanism 302 b. In the in clination mechanism 302 a, one end of each oftwo support shafts 320 and 322 is fixed onto the bottom of the housing12 and the other end thereof is rotatably attached to the lower surface202 of the stage 200 by a hinge (not shown). A rotational axiscorresponds to straight line 325 that connects joint 321 between thesupport shaft 320 and the stage 200 to joint 323 between the supportshaft 322 and the stage 200. Thus, the inclination mechanism 302 b doesnot include a rotational axis as an independent member. The supportshafts 320 and 322 do not have to stand perpendicular to the stage 200.The 200 is inclinable around the straight line 325 by moving up and downoperating shaft 326 that is connected to the stage 200 apart from thestraight line 325.

The support shaft 310 as a rotational axis is a member independent ofthe stage 200 in FIG. 6. However, another (not shown) one-dimensionalinclination mechanism may be adopted by processing part of the stage 200into a pair of protrusions, and protruding these protrusions from thehousing 12 to serve as a rotational axis. In this case, theone-dimensional inclination mechanism does not contain a rotational axisas an independent member, but the stage 200 has this function instead.

The moment application means is not limited to the direction indicatordial 312 that directly applies a moment to the support shaft 310. Forexample, rather than the direction indicator dial 312, if operatingshaft 328 is coupled to the stage 200 parallel to the support shaft 310,as in inclination apparatus 300 c in FIG. 11, an operator may apply amoment to the stage 200 around the support shaft 310 by moving up anddown in the drawing the operating shaft 328 which protrudes from thehousing 12. In this case, it is similar to FIG. 6 that the stage 200 isrotatable around the support shaft 310, but different from FIG. 6 thatthe support shaft 310 does not necessarily have the end 310 a whichprotrudes from the housing 12. The hole 16 in the housing 12 in whichthe operating shaft 328 moves would be formed as an arc, but could havea different shape as the shape of the operating shaft 328 changes.Needless to say, a position of the operating shaft 328 is not limited tothat illustrated.

Although the operating shaft 328 is a member independent of the stage200 in FIG. 11, it is possible to process part of the stage 200 into aprotrusion, and protrude the protrusion from the hole 16 in the housing12, making this serve as the operating shaft 328. Therefore, in thiscase, the one-dimensional inclination mechanism does not include themoment application means, but the stage 200 has this function instead.

If the stage 200 has the functions of the rotational axis and the momentapplication means, the stage 200 may additionally have functions of thesecuring mechanism, returning device, display, omitting inclinationdevice 300 in FIG. 1. Such barcode scanner 10B is shown in FIG. 12. FIG.18 shows a case where the CPU 400 automatically controls such stage 200.

FIG. 13 shows inclination apparatus 300 d having another one-dimensionalinclination mechanism 302 d. The inclination mechanism 302 d includesplate support member 330 which is engaged with the lower surface 202 ofthe stage 200 at one end thereof, support shaft 331 as a rotational axiswhich penetrates through the stage 200, and operating shaft 332 which isattached to the other end of the support member 330.

The support shaft 331 is fixed onto the stage 200, and supportedrotatably by the housing 12. The operating shaft 332 penetrates outsidethe housing 12 through arc 17 that is formed in the housing 12. Anoperator may apply a moment to the support member 330 and the stage 200by moving right and left in the drawing the operating shaft 332. In thisembodiment, the operating shaft 332 is spaced from the support shaft 331of the stage 200 by a predetermined distance.

The support member 330 and the operating shaft 332 may be integratedinto one member. The support member 330 is not limited to a plate-shapedmember, but may be formed as an L-shaped rod so as to serve as theoperating shaft 332, omitting the operating shaft 332. As stated, thestage 200 may have one or both of these functions. Processing part ofthe stage 200 may make the support shaft 331. A position and shape ofthe support shaft 331 are not limited to those shown in FIG. 13, similarto the above embodiments.

The one-dimensional inclination mechanism may thus use, but is notlimited to, any of the above concrete structures. A description will nowbe given of the inclination mechanism 302 as a two-dimensionalinclination mechanism.

The two-dimensional inclination mechanism is one which broadly inclinesthe stage 200 two-dimensionally, but not limited to two orthogonal axes.It is similar to the one-dimensional inclination mechanism that anoperator inclines the stage directly or indirectly by applying a momentto the stage 200 via an operating point that is located outside thehousing 12.

A description will now be given of inclination apparatus 300 e havingtwo-dimensional inclination mechanism 302 e which inclines the stage 200a two-axially, with reference to FIGS. 14 and 15. The inclinationmechanism 302 e includes support shafts 340 and 342, stage 344,different from the stage 200 a, which mounts the optical unit 100,direction indicator dial 346 engaged with the support shaft 340,direction indicator dial 348 engaged with the support shaft 342, hinge350 which engages the stage 200 a with the stage 344, spring member 352,and cam 354.

The support shaft 340 is coupled to the lower surface of the stage 344by securing members 356 and 358. As far as the support shaft 340 rotatestogether with the stage 344, an arbitrary position and structure may beselected for the securing members 356 and 358. For example, the securingmembers 356 and 358 may be comprised of the levers 319 a and 319 b, asshown in FIG. 7.

The stage 344 is coupled to the stage 200 a by the hinge 350. As thesupport shaft 340 rotates, the stage 344 that is integrated with itrotates together. The stage 200 a also rotates with the stage 344 aroundthe support shaft 340 since the hinge 350 connects the stage 200 a withthe stage 344 while prohibiting them from relatively rotating in arotating direction of the support shaft 340. Thereby, an operator mayincline the stage 200 a around the support shaft 340 by twisting thedirection indicator dial 346.

The stage 200 a is rotatable relative to the stage 344 by the hinge 350(in direction C in FIG. 15). The direction C is orthogonal to arotatable direction of the support shaft 346. The stage 200 a is forcedclockwise by the spring member 352.

The support shaft 342 is connected to a top surface of the stage 344 bya securing member (not shown) similar to the securing members 356 and358. The cam 354 is coupled to and rotated with the support shaft 342.The cam 354 is located between the hinge 350 and the spring member 352,and contacts the lower surface 202 of the stage 200 a. As far as the cam354 inclines the stage 200 a when rotating with the support shaft 342,by a different height which corresponds to the rotational angle, itsshape is not limited to the illustrated one. The cam 354 is formed as acylindrical shape and the support shaft 342 is shifted from the centerof the cylinder in FIG. 15, but it is apparent that the cam 354 may havea shape similar to the direction indicator dial 348. Thereby, theoperator may incline the stage 200 a around the hinge 350 by a heightcorresponding to the rotational angle by twisting the directionindicator dial 348 and rotating the support shaft 342 and the cam 350.

Securing mechanism 304 e, returning device 306 e, and display 308 e ofthe inclination apparatus 300 e shown in FIGS. 14 and 15 may utilizethose shown in FIG. 6, and a description thereof will be omitted. Thespring member 352 serves as the returning device around the supportshaft 342.

Next follows a description of a two-dimensional inclination mechanismthat broadly two-dimensionally inclines the stage 200. First, adescription will now be given of inclination apparatus 300 f havingtwo-dimensional inclination mechanism 302 f of the present invention,with reference to FIG. 16. FIG. 16 schematically shows the inclinationmechanism 302 f, omitting the optical unit 100. The inclinationmechanism 302 f includes support member 360 located beneath the centroidof the stage 200 b, spring members 362 which keep the stage 200 bhorizontal, and compression means 364 which apply forces onto the stage200 b from the top of the stage 200 b. In FIG. 16, the two-dimensionalinclination mechanism 302 f has four spring members 362 and fourcompression means 364.

As far as the support member 360 properly serves as a fulcrum ofinclination for the stage 200 b, it has an arbitrary shape. Referring toFIG. 16, a dent (not shown) is formed at the bottom of the stage 200 band the support member 360 has a conical shape having top 361 that isprocessed round so as to be partially engageable with the dent of thestage 200 b. Alternatively, the support member 360 may have a polygonpyramid or a sphere shape.

Each spring member 362 is connected to the bottom of the housing 12 atone end thereof, and the lower surface 202 of the stage 202 b at theother end thereof. The spring member 362 is adjusted so that no springforce applies to the stage 200 b at a horizontal state (initial state).The number and positions of springs are determined in accordance withthe number and positions of compression means 364 so that the stage 202b becomes stable. Therefore, the spring member 362 may be provided belowthe compression means 364. Alternatively, an elastic member other thanthe spring member 362 may be provided under the stage 200 b, forexample, an elastic sponge that envelops the support member 360 underthe stage 200 b.

The compression means 364 apply compression or tension forces to cornersof the stage 200 b, and may adopt any structure. It is not necessary toprovide four spots as shown in FIG. 16. The compression means 364 ismade, for example, by a link that is connected to the stage 200 bthrough a hinge. Referring to FIG. 16, working one or more compressionmeans 364 would apply a moment around the top 361 of the support member360. For example, when the compression means 364 is made of a link, anymethod known in the art can be applicable to secure the link andindicate the moving amount. The spring member 362 serves as thereturning device.

A description will now be given of the CPU 400 shown in FIG. 1. The CPU400 is connected to the A/D converter part 164 of the optical unit 100,the light control circuit 112, the angle detecting device 146, and themotor drive circuit 148. The CPU 400 is also connected to the interfacepart 410, the display part 420, the speaker 422, and an external powersource (not shown).

The CPU 400 includes a ROM, a RAM, a timer, an I/O controller, etc. (notshown), and runs based on a program stored in the ROM or RAM.

The CPU 400 controls the light control circuit 112 by a method known inthe art. The CPU 400 can control each element so that it may enter anenergy-saving mode when the timer (not shown) detects that the barcodescanner 10 has not used for a long time.

The CPU 400 sends an angle signal to the angle detecting device 146 andthe motor drive circuit 148, thereby controlling a rotational angle ofthe motor 144 (and the reflection surfaces 142 of the polygon mirror140).

The CPU 400 receives a digital signal from the A/D converter part 164 ofthe light receiving part 160 and recognizes the barcode data. A barcodeis recognized from data written down its top, middle, and end in apredetermined format. The CPU 400 judges that the data is valid whenrecognizing that the received digital data includes all of these data,and sends the data to a POS terminal via the interface part 410.Simultaneously, the CPU 400 may switch on and off green light on thedisplay 420, and bleeps from the speaker 422, notifying an operator thatthe data has been validly recognized.

On the other hand, the CPU 400 judges that the data is invalid when itcould recognize only part of the data or when the data did not complywith the predetermined format. The CPU 400 then switches on and off redlight on the display 420, and optionally gives an alarm sound from thespeaker 422. Thus, the CPU 400 notifies the operator of the invalidreading and prompts him/her to do reading over again. Incidentally, adescription will be given later of control of the CPU 400 over theinclination apparatus 300 when the CPU 400 recognizes the part ofbarcode data.

Next follows a description of barcode scanner 10C in which the CPU 400automatically controls the inclination apparatus 300, with reference toFIG. 17. In this case, the CPU 400 controls the inclination apparatus300 based on the program stored in the ROM or RAM (not shown). As shownin FIG. 18, the CPU 400 may control the stage 200 when the stage 200serves as the inclination apparatus 300, omitting the inclinationapparatus 300. However, this case would be easily understood from thedescription of control of the CPU 400 over the inclination apparatus300, and a description thereof will be omitted.

The CPU 400 in advance stores an optimal inclination angle for eachoperator in the ROM (not shown), and may control the inclinationapparatus 300 based on it.

In this case, the CPU 400 obtains ID number data from the interface part410 that the operator entered in the POS terminal, picks up inclinedangle information corresponding to the ID from the ROM, and controls theinclination apparatus 300 based on that information. In this way, theoperator may always obtain the optical unit 100 inclined at the optimalangle by simply entering his/her ID into the POS terminal.

When the CPU 400 does not store angle information for an operator, theCPU 400 conducts a simulation in accordance with a program stored in theROM and detects the optimal angle information for the operator. Thereare several kinds of simulations, such as a method in which the operatorrepeats a trial reading, detects the optimal inclined angle, and entersit in the CPU 400, and a method in which the CPU 400 automaticallydetect the inclined angle and stores it. Moreover, even after the CPU400 obtains the optimal inclined angle for a certain operator, it mayupdate the optimal inclined angle periodically (for example, when thenumber of reading errors exceeds a predetermined times per unit time) orwhen the operator desires so by conducting over again the former methodor the latter automatic detecting method. Optionally, the CPU 400 doesnot store an optimal inclined angle every operator and always performsan automatic detection by the latter method.

When an operator detects the optimal inclined angle and enters it intothe CPU 400, the operator enters information of inclined direction thatindicates whether a merchandise having a barcode moves from left toright or right to left viewed from the operator. Then, the operatormakes the CPU 400 incline the stage 200 every predetermined angle (forexample, five degrees) and enters the angle optimal to him/her into theCPU 400. Optionally, the CPU 400 may automatically detect and store theoptimal inclined angle based on the reading success rate. When anoperator enters the inclined angle, he/she may utilize the POS terminalor a keyboard etc. connected to the barcode scanner 10.

When the CPU 400 automatically detects an inclined angle, the CPU 400may detect the optimal inclined angle by detecting a position of astationary barcode or by detecting a path of a moving barcode. In eitherevent, when information indicative of a moving direction of merchandise(i.e., whether it moves left to right or right to left) is enteredpreviously, the CPU 400 would be able to detect the optimal inclinedangle faster.

When the CPU 400 detects an inclined angle by detecting a position of astationary barcode, an operator moves a barcode (or merchandise) to areading area peculiar to him and stops the barcode there. There areseveral methods of detecting a position of the barcode.

First of all, there is a method in which the CPU 400 automatically andsequentially inclines the stage 200 by every predetermined angle (forexample, five degrees) and detects an angle when it acquires lightreflected from a barcode. In this case, the CPU 400 may adopt atwo-stage searching method. The CPU 400 initially conducts a generalsearch which uses a broad angle (for example, ten degrees) so as toroughly detect a barcode position, and the switches to a precise searchwhen it detects part of the light reflected from the barcode, therebydetecting the precise position of the barcode.

A sensor may detect a barcode position. For example, as shown in FIG.19, the barcode scanner 10C has product detecting sensors 366 andindicator lamps 368 on the housing 12. Needless to say, positions andarrangements of the product detecting sensors 366 and the indicatorlamps 368 are not limited to those shown in FIG. 19. The productdetecting sensors 366 are arranged in the longitudinal and lateraldirections, covering the read window 14 at the top of the housing 12,and their outputs are connected to the CPU 400. The product detectingsensor 366 detects a shadow of merchandise and/or a barcode, and therebydetects its rough position. Any known sensor is applicable to theproduct detecting sensor 366. The CPU 400 controls inclination by theinclination apparatus 300 based on a detection signal of the productdetecting sensors 366.

The indicator lamp 368 indicates a position of scanning pattern (or areading area) emitted from the optical unit 100 on the inclined stage200, and informs an operator of it. The indicator lamp 368 turns on inaccordance with an instruction from the CPU 400. Thereby, an operatorrecognizes that a barcode should be approached to the reading areaindicated by the indicator lamp 368.

Where the CPU 400 detects an optimal inclined angle by detecting amoving path of a barcode, an operator is required to move a barcode (oractually a merchandise) along his moving path once or several times. TheCPU 400 may detect the barcode moving path based on the detection signalof the product detecting sensors 366 or may detect the optimal inclinedangle by making the inclination apparatus 300 incline the stage 200randomly, and detecting the barcode moving path from the light reflectedfrom the barcode at that time.

When the product detecting sensor 366 is used, there are provided aplurality of product detecting sensors 366 on the housing 12. The CPU400 may detect a barcode moving path by tracing the product detectingsensors 366 which respond to barcode's shadow which moves as the barcodemoves. Referring to FIG. 20, a description will be given of an exemplarycontrol method in which the CPU 400 detects the optimal inclined angleby detecting a barcode moving path, using the product detecting sensors366.

Initially, the CPU 400 judges whether the barcode scanner 10C having thestage 200 at an inclined angle in an initial state (or operated state)could read a barcode (step 702). Such a judgement is based on whetherthe CPU 400 or the POS terminal connected to it could understand theread barcode data.

If the barcode is normally read out, then the result is output to thePOS terminal via the interface part 410 (step 704), and the CPU 400maintains the inclined angle at that time. In the step 702, if thebarcode cannot be read, the CPU 400 checks the inclined angle of thestage 200 by the inclination apparatus 300 (step 706). Optionally, astep of judging whether the number of reading errors exceeds apredetermined times (for example, three times continuously) may beinserted between the steps 702 and 706. In that case, only if the numberof reading errors reaches the predetermined times, the procedure is fedto the step 706, otherwise is fed back to the step 702, prompting theoperator to repeat the reading operation.

Next, the CPU 400 obtains information relating to the barcode movingpath from the product detecting sensors 366 (step 708), calculates theoptimal inclined angle based on the it, and controls the inclinationapparatus 300, thereby modifying the current inclined angle to theoptimal inclined angle (steps 710 and 712). In this case, it isconceivable that the barcode moving path by the operator wasaccidentally abnormal to the operator, so the CPU 400 may prompt theoperator to move the barcode several times, and calculate the optimalinclined angle from the averaged moving path.

Control of the inclination apparatus 300 is conducted, for example, bycontrolling driving of the motor 370 which will be described withreference to FIG. 22. Thereafter, the barcode is read with the optimalinclined angle (step 714), but optionally the CPU 400 may inform and/orindicate the operator after the step 712 before the step 714 that theoptimal inclined angle has been set.

If the reading operation succeeds, the CPU 400 outputs the result to thePOS terminal (step 704), and if the reading operation fails, the CPU 400prompts the operator to repeat the reading operation since the inclinedangle has already been set to be optimal (step 716).

A barcode moving path is also detectable by utilizing light reflectedfrom the barcode. A description will now be given of the CPU 400 in thiscase. The scanning pattern emitted from the optical unit 100sequentially moves in the space as the motor 144 rotates. When thescanning pattern properly goes across the entire surface of the barcode,the reading operation succeeds. However, when the scanning pattern goesacross only part of the barcode, for example, the read data becomesincomplete. The CPU 400 may monitor this information momentarily,calculate a position of the scanning pattern which reads (even part of)data, and make the inclination of the stage 200 follow the calculationresult.

For example, as shown in FIG. 4, a beam is emitted (as a scanningpattern) in three directions from one stationary mirror 152 as thepolygon mirror 140 rotates and each reflection surface 142 changes aninclined angle. For instance, as shown in FIG. 21, a pair of V mirrors154 generate V patterns 155 a through 155 f, a pair of H mirrors 156generate H patterns 157 a through 157 f, and one Z mirror 158 generatesZ patterns 159 a through 159 c. The generation is repeated, by therotation of the polygon mirror 140, in the order of 155 a, 157 a, 159 a,155 d, 157 d, 155 b, 157 b, 159 b, 155 e, 157 e, 155 c, 157 c, 159 c,155 f, and 157 f, and a barcode is recognized in this order. Therefore,if the barcode data enters in the order of 155 d, 155 e, and 155 f, forexample, the CPU 400 recognizes an area of the moving path is close to155 d through 155 f and the moving direction is left to right in FIG.21. Based on this information, the CPU 400 may generate a control signaland control the inclination apparatus 300. Since the CPU 400 obtains anentry order of the barcode data in step 708 (for example, the order of155 d, 155 e, and 155 f) the control method in this case is similar tothe procedure shown in FIG. 20.

Next, a description will now be given of an operation of the CPU 400when the inclination mechanism 302 comprises the one-dimensionalinclination mechanism shown in FIG. 22. The structure is similar to thatin FIG. 7 except for the automatic inclination, and a duplicatedescription will be omitted.

The one-dimensional inclination mechanism shown in FIG. 21 includesmotor 370, gearbox 371, motor drive circuit 372 which drives the motor370, support table 373 which supports the motor 370 and the gearbox 371,potentiometer 374 as an angle detecting device which detects an inclinedangle of the stage 200, and support shaft 310 which is connected to androtatable with the stage 200 and also connected directly or indirectlyto and rotatable with the motor shaft (not shown) of the motor 370. Themotor drive circuit 372 and the potentiometer 374 are connected to andcontrolled by the CPU 400. The CPU 400 obtains angular information ofthe stage 200 from the potentiometer 374, and controls the motor drivecircuit 372 based on this information.

The gearbox 371 serves to reduce a speed of the motor 370 and increasetorque to be applied to the support shaft 310. Thereby, even the smallmotor 370 can secure the torque enough to incline the stage 200.

It is understood that when the stage 200 serves as the support shaft 310the motor 370 is directly connected to the stage 200.

In general, no securing device which secures the support shaft 310 (andthe stage 200) (such as, the gear 314 and the lock pin 316 shown in FIG.6) is required in the inclination apparatus 300 g (inclination mechanism302 g) shown in FIG. 22. This is because that the support shaft 310 isconnected to the motor shaft (not shown) of the motor 370, and the motorshaft and the support shaft 310 stops, when the motor drive circuit 372stops electrifying the motor, in that state. This is common to thefollowing two-dimensional inclination mechanisms having similarstructures.

A return to a predetermined position is realized simply by a program(which reversely rotating the motor 370, for example) stored in the CPU400 or the motor drive circuit 372 in the inclination mechanism 302 gshown in FIG. 22. Therefore, no spring member is required to connect thelower surface 202 of the stage 200 to the bottom of the housing 12. Thisis common to the following two-dimensional inclination mechanisms havingsimilar structures.

No display is generally required in the inclination mechanism 302 g inFIG. 22. The primary purpose of the display is to notify the operator ofthe inclined angle for use with the next operation, but the CPU 400memorizes the optimal inclined angle for the next operation for eachoperator. As a result, the operator does not have to memorize it, andthe direction indicator dial 312 is not required generally. However, ifnecessary, the angle detecting device 374 and/or an angle displayconnected to the CPU 400 may be independently provided. Such an angledisplay is useful for those operators who would like to actuallyreconfirm his/her optimal inclined angle. This is common to thefollowing two-dimensional inclination mechanisms having similarstructures.

The potentiometer 374 is connected to variable resistor 375 via leadline 376 a and 376 b. The variable resistor 375 may apply resistanceresponsive to the rotational angle of the support shaft 310 to thepotentiometer 375. When the input voltage is made constant (for example,DC 5V), the resistance value of the variable resistor 375 can bedetected by measuring the output voltage, whereby the rotational angleof the support shaft 310 can be detected. The motor drive circuit 372serves as the moment application means.

Next, referring to FIG. 23, a description will be given of inclinationapparatus 300 h (inclination mechanism 302 h) which is an automaticinclination version of the inclination apparatus 300 b shown in FIG. 10.The inclination mechanism 302 h further includes, in addition to theelements of the inclination mechanism 302 b, angle detecting device 374which detects an inclined angle of the stage 200, moving device 376which moves the operating shaft 326, and drive device 378 which drivesthe moving device 376. The moving device 376 and the drive device 378may broadly utilize any known device in the art. For example, a motorwhich attaches a cam to the motor shaft is used for the moving device376 and a motor drive circuit is used for the drive device 378. In thiscase, the CPU 400 may incline the stage 200 by the predetermined angleby controlling a moving distance of the operating shaft 326 (which isexpressed by the rotational angle of the motor shaft).

As shown in FIG. 11, where the operating shaft 328 is provided, the CPU400 moves the operating shaft 328 up and down. The control method of themoving distance of the operating shaft 328 is similar to those for themoving device 376 and the drive device 378. This is also similar to acase where the support member 330 and the operating shaft 332 areprovided as shown in FIG. 13.

Referring to FIG. 24, a description will now be given of inclinationapparatus 300 i (inclination mechanism 302 i) which is an automaticinclination version of the inclination apparatus 300 e shown in FIG. 14.The inclination mechanism 302 i includes, instead of directionindicators 346 and 348, in the elements of the inclination mechanism 302e, motors 380 and 381, motor drive circuits 382 and 383 which drive themotors 380 and 381, angle detecting device 384 which detects an inclinedangle of the stage 200 a, and angle detecting device 385 which detectsan inclined angle of the stage 344. The support shaft 340 is connecteddirectly or indirectly to and rotatable with the motor shaft (not shown)of the motor 380, whereas the support shaft 342 is connected directly orindirectly to and rotatable with the motor shaft (not shown) of themotor 381. The motor drive circuits 382 and 383 and the angle detectingdevices 384 and 385 are connected to and controlled by the CPU 400. TheCPU 400 obtains angular information of the stages 200 a and 344 from theangle detecting devices 384 and 385, and controls the motor drivecircuits 382 and 383 based on this information.

When the stage 200 a and/or the stage 344 serve as the support shafts340 and 342, the motors 380 and 381 are connected to the stages 200 aand 344.

Each of the angle detecting devices 384 and 385 is similar to the angledetecting device 374. A method for the CPU 400 to obtain the optimalinclined angle is basically the same as that for the one-dimensionalinclination mechanism, but it is necessary to heed that the rotary shaftof the stage 200 a is not the support shaft 342 but the hinge 350 (seeFIG. 15) in FIG. 24. Therefore, the CPU 400 need in advance memorize therelationship between the rotational angle of the support shaft 342 andthe inclined angle of the stage 200 a.

In automatically controlling the inclination apparatus 300 f shown inFIG. 16, the CPU 400 may control an inclination angle of the stage 200 bby controlling a moving distance of the compression means 364. Themoving distance of the compression means 364 is similarly controlled, asshown in FIG. 23, for example, by the angular detecting device 374connected to the stage 200 b, the moving device 376 connected to thecompression means 364, and the drive device 378 connected to the movingdevice 376.

As briefly shown in FIG. 25 which omits the optical unit 100,inclination apparatus 300 j (inclination mechanism 302 j) may includefour support members 390 which are hinged at the lower surface 202 c ofthe stage 200 c. Four joints between these four support members 390 andthe stage 200 c correspond to corners of a square or a rectangle. Thestage 200 c may be inclined in an arbitrary direction by simultaneouslymoving up or down the adjacent two support members 390. The CPU 400similarly controls a moving distance of the compression means 364, asshown in FIG. 23, for example, by using the angular detecting device 374connected to the stage 200 c, the moving devices 376 connected to eachsupport member 390, and the drive device 378 connected to each movingdevice 376.

Optionally, even when the CPU 400 automatically controls the inclinationapparatus 300, an operator may change the setting by manipulating akeyboard near the barcode scanner 10. This is especially useful to avoiddouble reading when the barcode scanner 10 a in FIG. 27 is used.

Irrespective of the manual and automatic adjustments, the inclinableangle may be restricted so that a scanning pattern does not go into eyesof an operator and/or a customer who stand at a predetermined positionand/or the stage 200 (or the optical unit 100) does not collide with theinner wall of the housing 12. The restriction to the rotatable range ofthe rotational axis is easily available, for example, by a mechanicalaction or a program in a ROM (not shown) in the CPU 400. The mechanicalrestriction is available as shown in FIG. 26, for example, where pin 315provided on the gear 314 coaxial to the support shaft 310 in FIG. 6 isallowed to move in cutout 19 in the housing 12. When the pin 315 rotatesclockwise in FIG. 26, its movement is restricted by end 19 b of thecutout 19. When the pin 315 rotates counterclockwise in FIG. 26, itsmovement is restricted by end 19 b of the cutout 19. For example, inorder to prevent the stage 200 in FIG. 6 from colliding with the housing12 as a result of inclination, a buffer cushion may be provided insidethe housing 12.

A description will now be given of concrete actions of the barcodescanners 10A through 10D of the present invention. In the followingdiscussion, the barcode scanner 10 generalizes the barcode scanners 10Athrough 10D and direction indicator dials and other elements are omittedin the drawings.

FIG. 27 shows the barcode scanner 10 installed on post 502 a. Keyboard500 a is provided next to the barcode scanner 10. The barcode scanner 10is connected to POS terminal 504. The barcode scanner 10 shown in FIG.27 is used as a longitudinal type. The height of the post 502 a isadjustable depending upon operator's height. In operation, the operatorpicks up a merchandise out of a shopping basket that he/she has placedunder the barcode scanner 10, makes the barcode scanner 10 read thebarcode, and returns the merchandise to the basket. However, if thebasket is placed in the scanning-pattern emitting direction of thebarcode scanner 10 and has merchandises with barcodes, there is a riskof double reading. As shown in FIG. 29, a method in which another basketis prepared and two baskets are placed at both ends of the barcodescanner 10 may avoid the double reading, but this method is restrictedif the cashier table is not wide enough to place two baskets.Accordingly, the operator changes the inclined angle of the stage 200 bya mechanical operation or entry through keyboard 500 a so that thebasket may be placed outside the reading area of the scanning pattern.

In use, the operator twists the direction indicator dial (not shown) orenters his/her ID through the keyboard 500 a, whereby he/she can obtainthe optimal inclined angle. In order to set a new inclined angle orchange the current inclined angle, the operator conducts theaforementioned simulation. The scanning pattern preinstalled at the timeof shipping in a factory is maintained even when the optical unit 100 isinclined, securing highly reliable reading operations. The scanningpattern meets the laser safety standards, securing highly safe reading.A longitudinal barcode scanner may be conveniently used as a lateralbarcode scanner after the store-refurbishing etc. simply by changing aninclined angle of the stage 200.

FIG. 28 shows the barcode scanner 10 that is embedded into the cashiertable and used as a lateral type. An operator stands at a front side inFIG. 28 and jumps a merchandise from left to right while making theintervening barcode scanner 10 read a barcode on the merchandise. Thisdrawing shows a typical example of the barcode scanner 10 of the presentinvention. An operator may advantageously stand at the opposite side inFIG. 28 after the store-refurbishing etc., and jump a merchandise fromright to left simply by changing an inclined angle of the stage 200.

The barcode scanner 10 shown in FIG. 29 is also installed on post 502 b,but the post 502 b is not adjustable in height. Keyboard 500 b islocated on the barcode scanner 10, and the cashier table has a room fortwo baskets. This drawing also shows one of the most typical examples ofthe barcode scanner 10 of the present invention.

FIGS. 28 and 29 each have similar effects to those of FIG. 27.

Referring to FIG. 30, a description will now be given of barcode scanner(two-faced scanner) 10E as one example of multi-faced scanners of thepresent invention. The multi-faced scanners are those barcode scannerswhich have a plurality of read windows on the housing. The two-facedscanners are those barcode scanners which have two read windows, andsome have bendable two parts each having a read window. The two-facedscanner 10E shown in FIG. 30 has bending angle α as an obtuse angle, butthe barcode scanner 10 of the present invention is applicable to onewhich has the bending angle α of an approximately right angle as shownin FIG. 31.

As the two-faced scanner 10E emits scanning patterns from two scannerparts 602 and 604, and scans a barcode from multiple directions, thusproviding a reading precision higher than the single-faced scanner. Morespecifically, the two-faced scanner 10E may improve the readingprecision by passing a barcode through an optimal reading area (sweetspot S) near foci (a point where a beam diameter becomes minimum) of twoscanning patterns emitted from these two scanner parts 602 and 604. Eventhough a barcode passes outside the sweet spot S, those barcodes whichhave wide bar intervals, like a barcode printed on a relatively largemerchandise (e.g., a six-roll pack toilet paper) are possibly readable.However, a barcode having narrow bar intervals put on a relatively smallmerchandise is not always readable properly. A two-faced scanner maykeep the sweet spot S wider than usual scanners.

The two-faced scanner 10E of the present invention has two scanner parts602 and 604 which are bendable at joint 601, guide indicator part 606and switch 608 attached to the scanner part 602, a pair of readingdirection indicators 610 attached to the scanner 604, and arrow mark 612which indicates the bending angle α between the scanner parts 602 and604, and scale 614.

In this way, the two-faced scanner 10E is variable in bending angle α.Optionally, the bending angle α may be fixed to the predetermined valueand made invariable. The scanner part 602 and/or the scanner part 604may have a collimeter lens etc., if necessary, so that an emitted beamhas a focus in the sweet spot S.

An operator changes the scanning-pattern emitting directions of thescanner parts 602 and 604 in accordance with the bending angle α,changing a position of the sweet spot S. The operator sets the bendingangle α to an experimentally optimal angle, confirming a value on thescale 614 indicated by the arrow mark 612.

Next follows a description of a relationship between thescanning-pattern emitting direction of the scanner part 602 and thebending angle α. Referring to FIG. 32, the scanner part 602 has alinkage including movable arm 616 and fixed arm 619. The movable arm 616includes end 617 which is rotatably connected to the stage 200 whichmounts the optical unit 100, and fixed end 618 which is rotatablerelative to the scanner part 602. On the other hand, the fixed arm 619is fixed onto the side of the stage 200, and includes end 620 which isconnected to the end 617 of the movable arm 616 and the stage 200, andfixed end 621 which is rotatable relative to the scanner part 602. Themovable arm 616 moves in an arrow direction in FIG. 32 as the scannerpart 602 moves relative to the scanner part 604 so that the bendingangle α may increase. Thereby, the ends 617 and 620, the stage 200, andthe optical unit 100 rotate counterclockwise around the fixed ends 618and 621 as fulcrums. Therefore, as the bending angle α changes, thescanning-pattern emitting direction of the scanner part 602 changesaccordingly.

For example, the two-faced scanner in FIG. 31 enables the scanner parts602 and 604 to emit scanning patterns in directions perpendicular to theread windows 603 and 605, respectively. Therefore, as shown in FIG. 33,the sweet spot S is formed near a position where focus distance (oroptimal depth) L from the scanner part 604 is L1. On the other hand, inthe two-faced scanner in FIG. 29, the scanner part 602 emits scanningpattern at acute angle with respect to the read window 603. Therefore,as shown in FIG. 33, the sweet spot S is formed near a position where afocus distance L from the scanner part 604 is L2. Small L (e.g., L=L1)is used to read small barcodes printed on a small merchandise, whereaslarge L (e.g., L=L2) is used to read large barcodes printed on a largemerchandise. For example, in an attempt to read out a barcode printed ona six-roll pack toilet paper, if L is set to be L1, the merchandisecollides with the scanner part 602 and cannot pass through the sweetspot S. When a barcode is located at the sweet spot S, two beams hit thebarcode, whereby they are reflected and scattered. The reflected lightthen returns to the optical unit 100 in a path reverse to the scanlight.

As shown in FIG. 35, the scanner parts 602 and 604 each generallycorrespond to one of the barcode units 10A through 10D. A variationwhich simplifies a structure is available; for instance, one CPU 400 maycontrol both scanner parts 602 and 604. Thus, even after the bendingangle α is determined, and the scanning-pattern emitting direction ofthe scanner part 602 is determined by the linkage shown in FIG. 31, thestage 200 (and optical unit 100) can be changed in inclined angle, ofcourse.

The guide indicator part 606 in FIG. 30 indicates a set value of thebending angle α, a size of merchandise corresponding to the set value(for example “L”, “M”, and “S”), an image which expresses the readingarea, information of whether the reading has been succeeded, informationof the read merchandise (such as, price), shopping information,manipulation information, breakdown information of each part, and thelike. The switch 608 may switch these information.

The guide indicator part 606 primarily serves to improve a workingefficiency by providing an optimal manipulation to an inexperiencedoperator. Thereby, the operator may secure the optimal manipulation byadjusting the bending angle α, changing the inclined angle of the stage200, and the like. Alternatively, the guide indicator part 606 may belocated at a position where a customer and the operator both can easilysee it, for example, at the top of the scanner part 602. Thus, the guideindicator part 606 can be used to improve service to customers, forexample, to have the customer confirm the price of the shopped goods, toprovide shopping information (for example, sales information) to thecustomer, etc.

The guide indicator part 606 is provided with the scanner part 602, butmay be formed as a different unit from the scanner part 602 orintegrated with the keyboard unit. The guide indicator part 606 is madeof an LED or LCD which indicate only letters, or a TFT or plasma displaywhich can indicate images, and the like.

The reading direction indicator 610 includes arrow marks. The arrow markcorresponding to a merchandise moving direction turns on. For example,as shown in FIG. 36, where a merchandise moves right to left, the rightarrow mark which indicates the moving direction turns on, and thescanner part 604 emits the scanning pattern in the right direction.

Further, the present invention is not limited to these preferredembodiments, but various variations and modifications may be madewithout departing from the scope of the invention. For example, thebarcode scanner of the present invention is not limited to those fixedonto a cashier table and the like, but is broadly applicable tohand-held type barcode scanners in which an operator approaches anoptical reading part to a barcode, and optical readers which emit ascanning pattern to an optically readable medium.

According to the optical reader of the present invention, the variableemitting direction of the scanning pattern enables uniform manufacturingof the optical reader, without distinction of longitudinal and lateraltypes and barcode moving directions. An operator may adjust an emittingdirection in accordance with his/her height and experience to obtainprompt reading operations without practicing manipulations necessary forthe conventional devices. Moreover, the maintained optimal scanningpattern provides a high reading reliance and meets the laser standardssafely.

What is claimed is:
 1. An optical device comprising: a first housing; asecond housing which is attached rotatably to said first housing; areflective mirror housed in said second housing; and a mechanism whichchanges an inclination angle of said reflective mirror in said secondhousing when an inclination of the second housing relative to said firsthousing changes, wherein said reflective mirror is attached to saidsecond housing via a first rotating fulcrum and connected through asecond rotating fulcrum to an arm which is attached to said secondhousing via a third rotating fulcrum.